ACER adopts third amendment to the aFRR Implementation Framework, harmonising FRR prequalification, switching, re-prequalification and termination rules for BSPs

ACER Decision No 12/2026 (18 September 2026) approves, with amendments, the TSOs' Common Harmonisation Proposal (CHP) annexed to the aFRR Implementation Framework (aFRRIF), establishing harmonised EU-wide rules for FRR prequalification, BSP terms and conditions, switching of reserve-providing units between BSPs, re-prequalification, termination of prequalification, and data exchange standards, following a multi-year TSO survey and consultation process and an ACER regulatory review that included a public consultation, working-level meetings, an oral hearing and Board of Regulators approval.

The decision creates a common EU framework for how balancing service providers demonstrate technical eligibility to offer automatic frequency restoration reserves, putting three prequalification routes (activation test, ex-post verification, fast-track) on equal legal footing to lower entry barriers for new and small aFRR providers while preserving TSOs' ability to safeguard system security, directly shaping competition and market access dynamics in the EU balancing energy market.

This is a parallel but legally distinct process to the mFRRIF third amendment (Decision No 13/2026) tracked separately, since it amends a different implementation framework (Article 21 aFRRIF) with its own CHP structure, submission (18 December 2025) and legal basis. Substantively, ACER's key market-design intervention is removing the default status of activation-test prequalification and placing all three approaches (activation test, ex-post verification, fast-track) on equal footing — a significant liberalisation of BSP market entry that TSOs contested throughout the written and oral procedure, particularly around timelines, RPG switching feasibility, and discretionary TSO powers flagged by the Belgian NRA. The unresolved tension between harmonisation depth and TSOs' request for national flexibility (via national terms and conditions for BSPs) will determine how much genuine cross-border consistency the CHP delivers in practice; ACER's approach of anchoring TSO discretion in NRA-approved national terms and conditions rather than in the CHP itself is a compromise that could still allow significant national variation in implementation of otherwise 'harmonised' processes.

Commission Regulation (EU) 2017/2195 (Electricity Balancing Guideline), Article 21; Commission Regulation (EU) 2017/1485 (SO Regulation), Articles 158-159; Regulation (EU) 2019/942, Article 5(2)(b)

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